Studies are continuing to understand the mechanism of induction in the liver of delta-aminolevulinic acid synthetase. The steps will be sought for in the conversion of alpha-ketoglutarte to delta-aminolevulinic acid in plants. A method is being developed to determine the rate of synthesis of delta-aminolevulinic acid in intact chick embryo liver cells in culture. BIBLIOGRAPHIC REFERENCES: Sassa, Shigeru, Granick, S. and Kappas, A. Annals of the New York Academy of Sciences. 1975, 244:419-440. The effect of lead and genetic factor on heme biosynthesis in the human red cell. Sinclair, Peter and Granick, S. Annals of the New York Academy of Sciences. 1975, 244:509-520.